The proposed 2-year study focuses on inhalant use among Mexican-American adolescents in low socioeconomic neighborhoods located in south central Texas. Its purpose is to examine posttreatment outcomes for 150 clients admitted during 1981-1984 to the Youth Advocacy Program in Austin, Texas. Drug use and related behavioral outcomes as well as biochemical medical status (using urine and blood sample analyses) will be examined after a 4-year follow-up period using a prospective, longitudinal research design. The results will help guide future drug abuse treatment and prevention strategies in Mexican- American communities. The research relies on a client-level data base operating since 1981 -- referred to as the Prevention Intervention Management and Evaluation System (PMES) -- for drug abuse prevention and intervention programs in Texas. This system includes background and baseline data on program admissions, as well as information on family environment and relations, peer activities, and psychological status variables recorded at program admission. The sample of 150 clients will be stratified according to level of inhalant use before program admission. Parallel interviews with parents will also be induced in the study. Drug use and other behavioral outcomes obtained in personal follow-up interviews with these samples (and with parents), along with the results of biochemical (blood and urine) analyses, will serve as a basis for assessment of behavioral, sociological, and physiological changes over time. Special emphasis will be given to treatment, family and peer relations, self-esteem, and drug use experiences as predictors in a prospective design of follow-up outcomes.